Reads the contents of the MDL query file into the specified
OEMolBase object. The atom and bond query features
present in the MDL file are attached as generic data to the related
atoms and bonds of the OEMolBase object. An
OEQMolBase object can be subsequently created from
this OEMolBase object by calling the
OEBuildMDLQueryExpressions
function. OEReadMDLQueryFile is a low-level reader and as such
will not call Clear on each
read.